1. Field of the Invention
The present invention relates to a tape cartridge constructed to restrict a rotation of a reel hub by a brake lock member when in non-use and to release the reel hub from locking when in use.
2. Description of the Prior Art
A 1-reel type tape cartridge has a single reel hub unit inside, and a tape-shaped recording medium is wound along the periphery of the hub. This type of tape cartridge is employed for storing backup data for a computer, and so forth. When this type of tape cartridge is loaded into a magnetic recording/reproducing apparatus for the computer, the tape-shaped recording medium wound along the hub periphery of the reel hub unit is led out and then rewound on a reel hub unit on the side of the magnetic recording/reproducing apparatus. Then, the tape-shaped recording medium runs between the reel hub units on both sides, whereby recording and reproducing are conducted.
In a conventional tape cartridge shown in FIGS. 11A through 11C as described above, when not used, prevention of slackening of the tape-shaped recording medium wound on a reel hub unit 130 rotatably accommodated in a case constructed of an upper case 120 and a lower case 220, involves restricting an unnecessary rotation of the reel hub unit 130 (refer to, e.g., Japanese Patent Application Laid-Open Publication No. 2002-343058). For attaining this, as illustrated in FIG. 11A, when not used, teeth 151 of a brake lock member 150 mesh with teeth 135 of the reel hub unit 130, thereby locking the reel hub unit 130 so as not to rotate. When used, a contact surface of a brake release member 160 contacts with a bearing portion 152 of the brake lock member 150 to raise the brake lock member 150 upward in FIG. 11B, thereby releasing the reel hub unit 130 from being locked by the brake lock member 150. Note that the brake lock member 150 has a protruded bearing portion 152 of which a front side end has substantially a curved-surface, and a surface, taking a face-to-face relationship with the curved-surface of the bearing portion 152, of the brake release member 160 is flat. Moreover, the brake lock member 150 is biased toward the brake release member 160 by an unillustrated biasing means (spring), and the brake release member 160 is structured to rotate together with the reel hub unit 130.
A further increase in storage capacity is demanded of the aforementioned tape cartridge used for storage etc of the backup data for the computer, and a tape feeding speed decreases because of an increased data transfer rate. Therefore, a rotating speed of the reel hub unit 130 rises when used. When in use, as shown in FIG. 11B, the brake release member 160 rotates with the rotations of the reel hub unit 130. In this case, the rotating brake release member 160 has the flat surface while the bearing portion 152 of the non-rotating brake lock member 150 takes the protruded shape having substantially the curved-surface. Hence, there might be a case that a central axis of the brake release member 160, which is defined as a central axis of rotation, deviates from a central axis of the bearing portion 152 of the brake lock member as a fixed portion. If deviated in an outer peripheral direction, a difference in peripheral speed occurs in a radial direction. The brake lock member 150 is influenced by this difference and receives a force to move in the outer peripheral direction. There, however, exists a biasing force given by the spring, and conversely the force acts to return to the original position. With this operation repeated, vibrations are caused to emit vibrating sounds. Further, the bearing portion 152 of the fixed brake lock member 150 receives a large frictional force of the rotation and might be thereby abraded.
Moreover, a built-in clearance is provided between the brake lock member 150 and the upper case 120 and, if the vibrations are extremely great, causes a large tilt of the brake lock member as illustrated in FIG. 1C. The result is that the teeth 151 of the brake lock member 150 butt against the teeth 135 of the reel hub unit 130, and a problem might occur, wherein the abnormal sounds are emitted and the teeth are chipped away.